The proposal includes three major areas of research with the following objectives: 1. Mechanism of Cholesterol absorption: a. to determine the influence of the unstirred water layer on the rate and extent of cholesterol absorption. b. To assess the role(s) of chylomicrons and VLDL and their apoproteins on the transport of "endogenous" and exogenous cholesterol. c. To evaluate the role of the microtubules in cholesterol uptake, esterification and/or release by the intestinal epithelium. 2. Studies with purified Cholesterol Esterase (sterol ester hydrolase) and its antibodies: a. To scale up purification using antibody-affinity chromatography. b. To determine, with spectral methods, the mechanism of bile salt activation of the enzyme. c. To determine the potential for autoimmunity against the enzyme. 3. Physiological and Pharmacological Influences on Cholesterol Absorption: a. To elucidate the mechanisms by which various dietary fibers influence absorbability. b. To determine the absorbability of seafood sterols and their influence on cholesterol absorption.